1. Field of the Invention
This invention relates to a method of hydrorefining an asphaltenic charge stock, i.e. converting the colloidally suspended asphaltenes to oil soluble components, by effecting the reaction utilizing a titanium sulfide catalyst which preferably also contains titanium chloride in an hydrogen atmosphere containing from about 10 to about 25 mol. percent of hydrogen sulfide.
2. Description of the Prior Art
In the development of alternative methods of hydrorefining asphaltenic feedstocks in such a manner as to convert the colloidal asphaltenic components to oil soluble compounds, a number of problems must be overcome. Generally asphaltenic feedstocks contain a variety of contaminants. The high quantity of sulfur generally present, mandates that the catalyst be sulfur tolerant. At the same time, the catalyst must function in such manner that the colloidal asphaltenes are converted into useful hydrocarbon fractions without the generally observed decomposition to coke, gas and light liquids deactivating the catalyst.
Both vanadium and titanium sulfide have been described in the prior art as sulfur tolerant hydrogenation catalysts by Pier et al in U.S. Pat. Nos. 2,038,599 and 2,127,383. However, the active life of these particular catalysts where one attempts to use them in the treatment of asphaltenic feedstocks is very short, generally on the order of one or two hours. Moreover, only certain forms of vanadium sulfide are active. Additionally, temperatures exceeding 380.degree. C. are required where the foregoing catalysts are used. I have observed that the activity of vanadium sulfides may be conserved by the addition of H.sub.2 S to the gas phase.
In accordance with the present invention I have discovered a new method for hydrorefining asphaltenic feedstocks whereby the colloidal asphaltenic component of such feedstocks is converted into oil-soluble hydrocarbon fractions, which method may be operated at much lower temperatures than heretofor previously possible. This result is obtained by selecting a specific titanium sulfide catalyst which preferably also contains titanium chloride and effecting the hydrorefining in a gas phase containing H.sub.2 S of measured amounts.